Bottom Line:
The results showed that NaCl had a synergetic effect with nitrate on the growth of S. europaea.The application of the Ca(2+) channel blocker LaCl3 not only caused a decrease in nitrate uptake rate, but also attenuated the promoting effects of NaCl on nitrate uptake rates.Based on these results, a possible regulatory network of NaCl-facilitated nitrate uptake in S. europaea focusing on the involvement of Ca(2+) signalling was proposed.

Figure 4: PCA, spot significant analysis, and functional classification of the identified proteins. (A) PCA of the different experimental groups. Samples plotted on the first two principal components (PCs) are shown. (B) Venn diagram showing the distribution of significant spots following two-way ANOVA. The numbers outside the parentheses are the total numbers of significant spots and at least one absolute variation was obtained above 1.5-fold by performing comparisons among the different treatments. The numbers in parentheses are the number of protein spots identified in the MALDI-TOF/TOF-MS. (C) Functional classification of 81 identified proteins. The percentage of proteins from each category is shown. The two most abundant categories, metabolism and cell signalling, were subsequently divided into subgroups.

Mentions:
2D-DIGE with pH 4–7 strips was used to separate root PM proteins, and ~2400 protein spots were found in each image (Fig. 3B; Supplementary Fig. S2 at JXB online). The 20 protein samples representing five biological repeats of each of the four treatments were assigned to 10 DIGE gels, which were labelled with Cy2, Cy3, and Cy5. A total of 30 images were acquired (Supplementary Table S1; Supplementary Fig. S2). After matching the 30 spot maps, 717 protein spots were found in 80% of them (Supplementary Table S2). PCA based on these 717 protein spots was performed to determine the distribution and similarities of different experimental groups. The five spot maps of each treatment were exactly clustered in the score plot (Fig. 4A), indicating high reproducibility among the replicate gels. Principal component 1 (PC1) explained 47.7% of the variance and separated the experimental groups according to NaCl treatment, whereas the axis PC2 accounted for 13.7% of the variance and separated the experimental groups according to nitrate treatment.

Figure 4: PCA, spot significant analysis, and functional classification of the identified proteins. (A) PCA of the different experimental groups. Samples plotted on the first two principal components (PCs) are shown. (B) Venn diagram showing the distribution of significant spots following two-way ANOVA. The numbers outside the parentheses are the total numbers of significant spots and at least one absolute variation was obtained above 1.5-fold by performing comparisons among the different treatments. The numbers in parentheses are the number of protein spots identified in the MALDI-TOF/TOF-MS. (C) Functional classification of 81 identified proteins. The percentage of proteins from each category is shown. The two most abundant categories, metabolism and cell signalling, were subsequently divided into subgroups.

Mentions:
2D-DIGE with pH 4–7 strips was used to separate root PM proteins, and ~2400 protein spots were found in each image (Fig. 3B; Supplementary Fig. S2 at JXB online). The 20 protein samples representing five biological repeats of each of the four treatments were assigned to 10 DIGE gels, which were labelled with Cy2, Cy3, and Cy5. A total of 30 images were acquired (Supplementary Table S1; Supplementary Fig. S2). After matching the 30 spot maps, 717 protein spots were found in 80% of them (Supplementary Table S2). PCA based on these 717 protein spots was performed to determine the distribution and similarities of different experimental groups. The five spot maps of each treatment were exactly clustered in the score plot (Fig. 4A), indicating high reproducibility among the replicate gels. Principal component 1 (PC1) explained 47.7% of the variance and separated the experimental groups according to NaCl treatment, whereas the axis PC2 accounted for 13.7% of the variance and separated the experimental groups according to nitrate treatment.

Bottom Line:
The results showed that NaCl had a synergetic effect with nitrate on the growth of S. europaea.The application of the Ca(2+) channel blocker LaCl3 not only caused a decrease in nitrate uptake rate, but also attenuated the promoting effects of NaCl on nitrate uptake rates.Based on these results, a possible regulatory network of NaCl-facilitated nitrate uptake in S. europaea focusing on the involvement of Ca(2+) signalling was proposed.